Hydraulic hoist



Nov. 6, 1928.

1,690,181 J. E. SEDERHOLM HYDRAULIC HOIST Filed May 12, 192?9 IN VEN Tofa J'OHN f. JEDER/ULM Patented Nov. 6, 1928.

UNITED STATES PATENT OFFICE.

JOHN E. SEDEBHOLM, OF ST. PAUL, MINNESOTA, ASSIGNOR '.IO AHERIAN HOIS'I d: DBBRIQX CO., OF ST. PAUL, IIINNESOTA, A PARTNERSHIP COMPOSED OF F. J'.

JOHNSON AND W. 0. WASHBUBN.

HYDRAULIC HOIST.

Application Med icy 1l,

This invention relates generally to improvements in hydraulic hoists, and more particularly relates to such hoists of the portable type, which are particularly adapted for use I in factories and machine shops for lifting and moving heavy articles, as for instance in the assembling of heavy machines, etc. This novel hoist is particularlyadapted to be suspended from an overhead su portin means such as a movable chain pul ey-bloc crane,

or other suitable means.

Hoists in use at the present time and particularly the well-known pneumatically operated type which are most commonly used, re-

quire the installation of air compressors, pipelines, hose connections, numerous fittings, etc. and are, therefore, costly to install. 'The maintenance cost of such a hoist is also high, caused by the useof numerous joints which have a tendency to become leaky from Wear and rough usage and must, therefore, be kept in continual repair in order that the hoist will be operative. The pistons of such hoistsare also the source of considerable inconvenience as the leather packings which are generally used become worn and must, therefore, be replaced. Such hoists have also been the source of serious damage caused by the lifting-hook thereof gradually lowering when the supply of air was cut olf, caused by a small leak, and in some cases when the air was again turned on the hook would move slowly upwardly and if accidently caught in a machine, might .cause serious damage thereto.

The novel hoist featured in this invention is of the hydraulic type, preferably using oil as a fluid. It is electrically operated and is provided with a simple one-hand control which is conveniently located and so arranged that the operator will have complete and accurate control of the operation of the lifting hook thereof at all times. It is very simple and inexpensive in construct-ion and is designed kfor the purpose of providing a hoist which will be efficient and positive in its performance A and will be safe to handle in the assembling of heavy machinery.

Important features of the invention reside in the arrangement of the pump within the piston chamber or cylinder, and the manner i924. serial No. 712,587.

the axes of the motor shaft, pump shaft, and piston. rod aligned, to permit disconnecting, and withdrawal axially of the cylinder.

These features individually and collectively make for compactness, particularly in a longitudinal direction, reduce leaks to la minimum, and eliminate the use of hose connections. Moreover, if there is a leak inthe pump, no loss of pump fluid outside of the cylinder can take place.

Another feature relates to the mounting, of the motor control switch in the release valve control handle, whereby no change of position of the hand of the operator with respect to the handle is necessary, to start the motor o1l to control the valve, both controls being obtainable by the one hand of the operator.

The object of this invention, therefore, is to provide an improved hoist.

In the drawings:

Figure 1 is a vertical sectional view of the lmproved hoist showing the lifting hook in raised position;

Figure 2 is a side elevation of the upper portionof the hoist; and

Figure 3 is a cross-sectional view on the line 3--3 of Figure 1 showing the preferred type of pump used.

In the selected embodiment of the invention here shown there is illustrated a hydraulic hoist comprising a cylinder 4 havingean annular flange 5 suitably secured to the lower end thereof, to provide a seat for the cylinder head 6 secured thereto by bolts 7. A piston rod 8 having a piston head 9, of ordinary construction, secured to the upper end thereof, is mounted for reciprocal movement within the cylinder 4. A lifting-.hook 11 is secured to the lower end of the piston rod 8 by means of a U-b0lt 12, Washer 13and nut 14, in threaded engagement with the rod.

A motor supporting bracketl or housing 15 issecured to the upper end of the cylinder, preferably by. means of threads 16. A motor 17 is mounted within this bracket and a cap 18 is suitably secured to the bracket 15 to provide a supporting means for the hoist. The upper end of the cap 18 is preferably provided with a pair of lugs 19 apertured to receive a pin 21 whereby the hoist may be secured to a suitable supporting means such as a crane hook, not shown. A suitable washer 20, preferably of rubber, is seated upon the upper end of the cylinder beneath lthe motor to prevent the oil from coming in contact with the motor.

The means provided for pumping the liquid from the upper end of t e cylinder to the lower end thereof or beneath the piston-head consists of a pump 22, mounted within the cylinder adjacent the upper end thereof. This pump is of the gear type and is directly connected to the motor by means of a coupling 23. A pi e section 24 is parallel with the axis ofthe cy inder, and has its upper end in communication with the pump through a bracket The lower end of this pipe is in communication with the lower end of the cylinder through a similar bracket 26 secured to the wall of the cylinder. A checkvalve 27, of ordinary construction, is interposed in this pipe between the brackets 25 and 26. lVhen the pump is actuated by the motor the oil will be pumped from within the cylinder above the piston head through the pipe 24 and into the lower portion of the cylinder beneath the piston-head 9. As the oil or fluid is pumped into the lower portion of the cylinder the piston-head and rod will gradually ascend carrying with it the load depending rom the hook 11. n

The means provided for releasing the piston and allowing the load to descend consists of a by-pass pipe 28 arranged adjacent the outer wall of the piston, preferably diametrically opposite the pipe 24. This lby-pass is parallel with the axis of the cylinder, and has its upper end communicating with the cylinder at a point above the pump 22. 'Ifhe lower end of the by-pass communicates with the lower end of the cylinder at a point substantially in alignment with the discharge opening of the pipe 24. This by-pass pipe 28 is similarl connected to the cylinder wall by means of rackets 29 and 31. A valve 32 is mounted in the lower bracket 31 and this valve has an arm 33 secured thereto, to which an operating rod 34 is connected. The valve 32 functions to control the flow of oil from the lower portion of the cylinder to the upper portion thereof, when it is desired to lower the lifting hook 11, and is normally held in closed position by means of a tension spring 35 having one end secured to the arm 33 and its other end secured to a bracket 36 suitably secured to the by-pass pipe 28. rlhe operating rod 34 is preferably provided with a T-shaped hand grip 37 whereby the operator may conveniently grasp the rod when it is desired to operate the hoist.

Brackets or elbows 25, 2G, 29 and 31 are welded, and the tubes 24 and 28 having screw threaded connections with the elbows to virtually provide a non-joint structure. The elbow 25 is provided with a threaded nipple which assists in securing the pump in position. The pump is otherwise held by screws engaged as shown in Figure 1. It will be noted that the axle of one of the gears of the two-gear pump lies in the axis of the cylinder. See Figure 3.

A switch button 38 is preferably mounted within the grip 37 and this switch is electrically connected to the motor by means of a conductor 39. Thus, it will readily be seen that by the provision of the hand-gri 37 and switch-button 38 the operator will iave complete and accurate control of the raising and lowering of the hook 11, and therefore of the load. A stop collar 41 is preferably mounted around the piston-rod 8 having its lower end resting upon the inner surface of the cylinder head 6 in order to limit the downward movement of the piston-rod and piston-licad.

In the operation of this novel hoist the motor 17 is started by means of the switch button 38. Starting of the motor will actuate the pump 22 which will cause the fluid to be pumped from above the piston head through the pipe 24 and check valve 27, to the lower portion of the cylinder and beneath the piston-head with the resultant raising of the load. When the load has been raised to the desired height the motor will be interrupted and the load will be suspended without any danger of the piston lowering, as is sometimes the ease when using pneumatically operated hoists. When it is desired to lower the load the operator will open the valve 32 by a slight downward pull upon the operating rod 34. Such openin of the valve 32 will permit the oil to flow rom beneath the piston through the by-pass to the upper portion of the cylinder, the check-valve 27 preventing the oil from returning through the pipe 24. Thus, the operator will have complete control of the operation of the hoist at all times.

I claim as my invention:

1. A vertically operable hoist including a cylinder, a piston, a rod for the piston operating through the bottom of the cylinder, a gear pump and means for circulatin fluid above and below the piston, the pump being wholly within the cylinder and above the piston, and a motor mounted upon the upper end of the cylinder immediately adjacent the pump and having a direct and detachable driving connection with one of the gears ofthe pump.

2. A vertically operable hoist including a cylinder, a piston, a rod for the piston operating through the bottom of the cylinder, a gear pump and means for circulating fluid above and below the piston, the ump being wholly within the cylinder and a ove the piston and a motor mounted upon the upper end of the cylinder immediately adjacent the pump and having a direct and detachable driving connection with the gear shaft of one of the pump gears, the connection being made in direction axially of the cylinder, pump gear shaft, and motor shaft.

. cylinder.

3. A hydraulic hoist comprising', a cylinder having a piston connected to' a lifting rod, which rod extends through the bottom wall of the cylinder, a gear pump wholly within the 5 cylinder immediately adJacent its upper end `and above the piston. the gear axles being parallel with the axis of the cylinder, valve-controlled fluid circulating passages one connecting the delivery side of the pump with the bottom ortion of the cylinder, and the other with t e cylinder at a point above the pump and below the piston, and a motor removably mounted upon the upper end of the cylinder, and having a shaft extending with in the cylinder and connected to drive one of the pump gear shafts, said motor shaft being disconnectable in a direction axially of the 4. A flliid hoist comprising a cylinder vertically arranged andfhaving a piston, having a lifting rod projecting through the bottom of the cylinder, a two gear pump within the cylinder immediatel adjacent the upper end thereof and including a gear chamber, and an intake passage leading from the cylinder to the chamber, valve controlled conduits respectively for leading liquid from the gear chamber to a pointadjacent the bottom of the cylinder, and for leading liquid upwardly from a point adjacent the bottom of the cylinder to a point above the pump, and a motor attached at the upper end ofthe cylinder above and immediately adjacent the pump and having a driving connection with the pump adapted to be disengaged when the motor is moved in a direction axially of the cylinder.-

In witness whereof, I have hereunto set my hand this 8th day of May, 1924.

JOHN E. SEDERHOLM. 

